Plastic mixture and process for making the same



'tures and Processes for Makin UNITED STATES PATENT OFFICE.

ELASTIC MIXTURE AND PROCESS FOR MAKING THE SAME.

No Drawing.

To all whom itmay concern:

Be it known that I, MORGAN K. ARM- STRONG, a citizen of the United States, and a resident of Winnetka, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Plastic Mixthe Same; and I do hereby declare that t e following is a full, clear, and exact description thereof.

This invention relates to an improved plastic mixture and to the process for making the same and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The object of the invention is to produce a novel and useful plastic mixture more particularly adapted for use as a body or filler for plaster wall boards, 'for molded forms and the like. The new plastic mixture is much cheaper and more economical to produce than are mixtures'now used for like purposes, and at the same time, it will, upon drying, harden to a degree having the requisite strength and the necessary adhesive qualities.

The improved plastic mixture includes as one of its ingredients, a full clay or a soil containing a comparatively large proportion of clay. To properl prepare the clay or soil, so that it is suitab e for use as such ingredient, it is first deflocculated as follows. I mix the clay or soil 'in its natural state, with water (preferably warm water). The clay or soil of the desired amount is placed in a suitable receptacle and the Water is thoroughly incorporated with it,the water being added in sufiicient quantity to make a thick creamy mixture of the consistency of what is known in the art as a clay slip. An electrolyte is then added, preferably sodium phosphate. ThBSOdlllIIl phosphate is added in the form of a weak solution, and is stirred thoroughly into the cla slip.

T e electrolyte, in this casesodiu m phosphate, not only acts as an efliclent aid to deocculation of the insoluble constituents of -The electrolyte is added in an amount sufficient to precipitate the greater .part of the soluble constituents of the clay. This will I Specification of Letters Patent.

' Application filed July 2, 1919. Serial No. 308,312.

Patented Feb. 24, 1920.

generally vary with different clays or soils contaimng clay, and the amount in each case may be determined by experiment.

After, or during, the process of deflocculation, a very small percentage (one-half to three-fourths of one per cent.) of some orgame colloid such as starch or dextrin, is added and thoroughly dissolved in the mixure.

The product thus made may be produced 1n large quantities and placed in suitable receptacles wherein it is kept on hand, ready for use when needed, to make the improved plastic mix.

When desired for use in a plastic mix for making plaster board, molded products or the like, finely grpund, calcined gy sum is added to the claymix taken from t e stock produced as above, and the two are thor oughly mixed together. The plastic mix is then ready for immediate use, as for example, on a machine for making plaster board, or for use in making molded forms or the like. The amount of calcined gyp sum iadded depends upon the purpose for which the plastic mix is to be used. In the case of the use of the plastic mix in making plasterboard, the proportions of the clay mix and of calcined gypsum are 40% of gypsum and of the clay mix.

In drying the plastic mix, after it has been incorporated in the plaster board, or has been molded into forms, to driveofl' the surplus water, any of the usual methods may be used for the purpose, but care must be taken to drive off the surplus water only,

. and the mix must not be submitted to a temperature that will recalcine the gypsum.

The combined water of the hydrates of the clay mix, as Well as the water contained in the mix, provide the water for hydrating the gypsum, when the plastic mix is being used for any of its intended purposes. The organic colloid, in this case, dextrin, retards the drying of the plastic mix and thus allows time for slower and better crystallization to take place.

I claim asmy invention: 1. The process of making a plaster mixture which consists in deflocculating clay or clay soil in a fluid, in the presence of an electrolytic agent, and of adding to and mixing with the deflocculated mass, finely ground, calcined gypsum.

2. The process of making a plaster mixture which consists in deflocculating clay or clay soil, reducing the same to the consistency of a clay slip, of adding an electrolyte adapted to precipitate the soluble constltuents of, the clay mix, of adding an organic colloid, and of then thoroughly incorporating in the mixture, finely ground, calcined gypsum.

3. A composition of matter includin clay or soil particles-Which have been de occulated in a fluid containing an electrolytic agent, and finely ground, calcined gypsum.

4. A composition of matter for the purpose set forth, including deflocculated clay or soil particles, and an electrolytic agent, and an organic colloid mixed with finely 15 ground, calcined gypsum.

In testimony that I claim the foregoing as my invention, I aflix my signature in the presence of two vwitnesses, this 30th day of June, A. D., 1919.

MORGAN K. ARMSTRONG.

Witnesses:

T. H. ALFREDS, D. DARRENOUGUE. 

